I've just ordered the battery for a relatives key start lawn mower and I once again began thinking about an electric start for my snow blower.  Right now in the colder weather I have to take out the spark plug, squirt some starting fluid into the chamber, put the plug back in and pull the cord.  I've gotten a hold of a 120 V electric motor but don't have an outside outlet for it to be plugged into and had begun thinking of using a battery to power the motor.   I tested the motor with a 12 volt car battery and it seems to run a bit slow to start the snow blower, 24 volts makes it run faster and should start the snow blower.  The other factor is the motor turns the engine faster so it starts fairly quick which I know from experience with my cousins snow blower which sometimes had a problem starting in the colder weather.
   The batteries are sealed lead acid and I was very surprised at the range of sizes and amp hours offered.  A 12 V 5Ah battery that I feel should do the job is only $11 and the size is only 3.5 by 2 3/4 by 4.  I had thought of the lithium batteries but the prices for these are pretty high.
Carl2

  This makes for an interesting project, with the help of a you tube vid I found where to look for the starter mounting, rusty bolts and screws were loose after using the oils.  It looks like the gears will mesh and the motor will mount.  The motor jumps when using AC voltage, I'll see if I can get an
idea of how much DC voltage is needed.  I'll try mounting the motor then try the AC power, next will be the DC power. 
Carl2

Nice little project Carl 

  Something to do and it gets me outside, the snow blower starts okay at 30 degree weather.  I should see if I can get an outdoor outlet put in somehow.  I need to get the motor to engage with the fly wheel teeth next and I'll probably use the AC then I could go to the DC. 
  The battery for the relatives lawn mower came in and I have to pick it up this is what got me started with the snow blower.  The lawn motor battery is real small, 2.8 A H, you plug it into a charger connector then turn a key to start.
Carl2

I mounted the motor again and connected the AC and got a grinding noise, tried a few times and got the same noise.  I took the motor off and checked the gear on the motor and the gear on the flywheel and neither one had any signs to indicate anything.  I measured the gears and it seems they should mesh.  Inspection with a flash light and magnifying glass on both gears again showed any signs of a problem.  To actually look at the flywheel gear a lot of metal covering has to come off.  Maybe I'll just wait till summer time with warmer weather. I'm glad I haven't ordered the batteries for it yet.
Carl2

  I've decided to get this project up and going I should stick with the AC so I'm putting in an outdoor AC outlet.  If and when I can get the motor to mesh with the gear then I'll think about a battery  setup.  Getting the metal off the snow blower to actually see the gears mesh seems like it will take a little time.
Carl2

  The outlet is attached to the outside of the house, a cord can be plugged into an outlet in the house supplies AC to the outside, much better than running a cord out the door.  I'd eventually like to connect the outside outlet to a light in the storage room so you flip a switch that turns on light and powers the outside outlet.  Right now I have to paint the plaster I put in the wall to repair the hole I made, do some cleaning and put things back in place.  When there are a few days of warm weather together I'll try working with the snow blower again.
Carl2

  A record breaking temp today and tomorrow is still pretty warm, I'd like to work on the snow blower but I've got inside work that needs to be finished.  I'll see it doesn't matter anyways.
Carl2

  I was able to get outside and work on the snow blower,  I removed the gas tank and removed some bolts and moved the cover so I could see the flywheel.  Being able to see what is going on helps, so the motor engages with the fly wheel and turns over the engine.  Maybe I'll get outside to today and try it with batteries and get an idea of how many are needed.
  I just got an idea, since the batteries are in series giving 36 volts we would need greater than 36 volts, simple arrange the 12 volt transformers in series 3 transformers give 36 volts.
Carl2

  I got out and tried the snow blower with the 3 batteries I have, I'm using a very small battery to be used for the electric start lawn mower in the group.  It starts easily, since it started within seconds I'm not concerned about the current I'm drawing.  Winter time starting will be a little harder but we'll see, ac will handle it for sure and I'm fairly certain the batteries will do the job.  The snow blower has a light so there is a generator, maybe it can charge the batteries. 
Carl2

  Fairly cold today but I got a chance to try out the electric start on the snow blower, it didn't start the first brief try but I primed it again and it started right up.  After that it starts easily with the pull cord, maybe I won't go to the battery mode, interesting but maybe a waste of money.
Really nice to plug in the cord and press the start, much easier than removing gloves taking out the plug and squirting starter fluid in during the cold weather.  Everything else went wrong today but having it start without problems was nice.
Carl2

I would call your project a success Carl2.

Nicely done